The body's natural clotting factors can form too much clot, or eventually not be able to effectively form any clot, leading to many issues. However, in patients with COVID-19, the researchers said, the clotting appears to be particularly severe.

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Last Updated: May 18, 2020, 10.58 AM IST

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HOUSTON: Critically ill COVID-19 patients face a high risk of developing kidney failure, stroke, and other complications associated with blood clot formation, according to a study which suggests that early tests may help save those severely affected by the disease.

The study, published in the Journal of American College of Surgeons, builds on growing evidence that COVID-19-infected patients are highly predisposed to developing blood clots.

In the study, the scientists, including those from the University of Colorado in the US, linked blood clotting measurements with actual patient outcomes.

The researchers said they are also currently conducting a randomised clinical trial of a drug that breaks down blood clots in COVID-19-infected patients.

"This is an early step on the road to discovering treatments to prevent some of the complications that come with this disease," said Franklin Wright, lead author of the study from the University of Colorado.

According to the study, patients who are critically ill, regardless of cause, can develop a condition known as disseminated intravascular coagulation (DIC).

In this condition, the blood of these patients initially forms many clots in small blood vessels, the scientists said.

The body's natural clotting factors can form too much clot, or eventually not be able to effectively form any clot, leading to issues of both excessive clotting and excessive bleeding, they explained.

However, in patients with COVID-19, the researchers said, the clotting appears to be particularly severe.

Citing COVID-19 case studies in China and from different parts of the world, they said the clots in these patients do not appear to dissipate.

Assessing the condition further among patients, the scientists saw the potential of using a specialised coagulation test to examine clotting issues in COVID-19 patients.

One such test they mentioned is the thromboelastography (TEG), which is a whole blood assay that provides a broad picture of how an individual patient's blood forms clots.

This test, according to the researchers, also reveals how long clotting takes in a patient, how strong these are, and how soon the clots break down.

TEG is highly specialised and used primarily by surgeons and anesthesiologists to evaluate the efficiency of blood clotting, but is not widely used in other clinical settings, the study noted.

"The COVID pandemic is opening doors for multidisciplinary collaboration so trauma acute care surgeons and intensivists can bring the tools they use in their day-to-day lives and apply them in the critical care setting to new problems," Wright said.

In the study, the researchers analysed 44 patients treated for COVID-19 infection between March 22 and April 20.

They assessed the outcomes for all patients who had a TEG assay as part of their treatment.

The scientists also evaluated the outcomes of the COVID-19 patients who were tested with other conventional coagulation assays such as the ones that measure the levels of the molecule D-dimer in their bodies.

D-dimer, they explained, is a protein fragment that is produced when a blood clot dissolves, whose levels are elevated when large numbers of clots are breaking down.

Those whose bodies were not breaking down clots most often required hemodialysis, and had a higher rate of clots in the veins, the study noted.

These patients, according to the researchers, could be identified by TEG assays showing no clot breakdown after 30 minutes, and a D-dimer level greater than 2600 nanogramme per millilitre (ng/mL).

Eighty percent of patients with both affirmative test findings were placed on dialysis, compared with 14 per cent who tested for neither finding, the scientists said.

According to the study, patients with positive test findings also had a 50 per cent rate of venous blood clots.

This was compared with zero per cent for those patients with neither finding, the scientists said.

"These study results suggest there may be a benefit to early TEG testing in institutions that have the technology to identify COVID-19 patients who may need more aggressive anticoagulation therapy to prevent complications from clot formation," Wright said.